ZIP Recovery Tools - Not *Exactly* an Endorsement

I was going to make this just a comment on my previous blog entry, but after spending a couple of hours trying various tools and making notes, the "comment" was getting longer than the original post. So it gets it's own entry.

I've kept poking at various tools to try to recover some of my data. It looks like most of it is
recoverable, at least with the right tool. The going price for zip
repair tools appears to be about $30. I haven't
forked over the money yet, as I'm still going over my options. If they
were under $20, I'd probably have already bought one, and if they were
$10-15 I might have bought a couple to try different things. But my
cheapness has paid off in that there is one free solution I've found
that appears to work well.

The Line-Up

pkzip and
7-zip are not the right tools in this case. These tools, which work just
fine for creating and extracting large zip files, are not so good at
recovering, at least not for whatever Microsoft did to my file.

DiskInternals ZIP Repair
(version 1.0) is free. Yes, FREE (I feel like one of those used-car
radio commercials except you can't really get the
scream-into-the-microphone effect in print). This is the only free tool
I've found and while it isn't as slick as some of the others listed
below, and the feedback is weaker, it does give you a quick running
total of how many files it has found as it scans. It is also fast (at
least for scanning) having completed its entire scan in less time than
it took me to write this paragraph (literally, it's paused right now
waiting for me to hit "Next" after the scan). Of course, the real test
is what did it find. From the list of files (which it displays only
after the scan is complete, not during), it appears to have found
everything the others did. I confess that the "Status" column with it's
"Excellent" and "Average" ratings on the files is not very illuminating
compared with, say ZipRepair Pro telling me exactly what it thinks is

FileInternals Zip Repair Tool
(version 3.3) trial is worth everything you pay for it; that is,
nothing. It warns that the file is over 5 Mb (duh, 5 Mb is tiny) and
then quits scanning after it finds the first file. Hard to evaluate on
that basis and certainly not something I would pay $5 for much less $30.

Nucleus Kernal Zip
(version 4.02) works, albeit s-l-o-w-ly as in go away and come back in a
few days. At least it seems to work as I stopped the scan after it
spent overnight chugging away and was about 25% complete on its scan
(trial version, like all of the rest below). 

SysTools Repair Zip
(version 3.0) crapped out with an error. I think it was partially my
fault. I asked it load the file and it gives almost no feedback; a small
red-text line at the bottom says "File Corruption Detected" but there
was no indication that it was doing anything, so I told it to load the
file again, got and error and Windows offered to close the program. I
did, but on retry, it looks like it is doing something, but
again, very slowly and it has yet to tell me about a single file being
found; every other tool (include pkzip and 7-zip) quickly list the files
at the beginning of the archive. It's been running for about 30 minutes
now and claims to be about 1% done.  

ZipRepair Pro
(version seems to be as good as Kernel Zip as far as
finding things and it is fast. The entire scan of the file took about
30-40 minutes. It gives good feedback, showing the files as it finds
them along with what it thinks is wrong. Only one file in the entire
archive is listed as "potentially unrecoverable." Even giving that
feedback is wonderful since it sets my expectations right at the start.


(version 3.10) quit after the third file, the one ZipRepair Pro listed
as "potentially
unrecoverable" and told me it had completed the analysis. Uhm, what
happened to the advertizing blurb "ZipRecover uses a unique SmartScan
technology from WinRecovery Software
that quickly diagnoses the situation and analyzes every byte on the zip
file to ensure all recoverable data will be retrieved." I guess not....
To add injury to insult (yes, that's backwards from usual), ZipRecover
is priced at $40. Priceless, no, worthless, yes.


Getting the Files Back

From my post, it might sound like I was saying pkzip and 7-Zip are no good. That's certainly not what I was trying to say. They are simply not the correct tools for recovering/correcting corrupted ZIP archives. However, after using the free DiskInternals ZIP Repair tool, which creates a new ZIP archive, Windows is unable to extract the files from it, giving an "Unexpected end of file" message. 7-Zip has no trouble at all with the file.

What can I say, Windows bites again.

Final(?) Result

7-Zip has completed extracting all of the files. Some of them were not, it seems, recoverable after all. However, the good news is that all of the unrecoverable files were derived files, not the original data. The original data files appear to all be good (hard to tell without going through them one-by-one, which I may do later). The "bad" files are the calibrated and aligned images used to create the final pretty picture. The original data and the calibration data all extracted without errors and the files appear to be of a reasonable size (which, of course, merely means they're full of something rather than nothing).